i) Technical Field
This invention relates to a sealed container for packaging, comprising a main container body with a lip or flange and a flexible top or covering that is sealed or bonded to the lip, wherein the top can be peeled to open the seal.
ii) Background Art
One method of mass-producing packaging containers is to form a number of container bodies at one time by making a number of shaped depressions in a single sheet of suitable material, usually of plastic or metal. The depressions may then be charged with the material to be packaged. A covering sheet or film is then bonded to this formed sheet with the shaped depressions. The covering might have its own shaped depressions, and could include printing on its surface. This bonding step results in a number of sealed containers, all joined together, because they were fabricated from one underlying sheet. This is followed by a die-cutting operation that separates the individual sealed containers, each having a lip and a tab, or a means to create a tab, that allows for manual opening of the seal and removal of the cover of the container.
In the past art, this tab has been provided for by a generally V-shaped portion that has extended from the lip of the container. To provide for this tab, the separation of the containers has required a die-cutting operation with non-circular dies. Among other problems, non-circular dies have higher fabrication and maintenance costs than comparable circular dies. Furthermore, a non-circular cut cannot be easily made with a rotating cutter.
The operation that separates the individual sealed containers could be sped up and improved if the die-cutting operation, using non-circular dies, was replaced by a cutting operation that produced a circular top on each container. Such a circular top could then be produced by a suitable rotating cutter or a circular die.